When Is Fixed Duration Fixed?

[DSnyder]

Does anyone anywhere know precisely how and when what conditions cause
fixed duration tasks to change duration?

We've had MPS Server 2003 implemented for a couple of years and have
just moved to managed time periods (labor is reported from 80+
resources via PWA).

But even before implementing managed time periods, we were getting
fixed duration tasks that change duration when accepting time. (I can
also get fixed duration tasks to change duration when I manually enter
more remaining work or work - usually when the task is at 100%
complete - this happens even when a finish on constraint is applied).
Now that we are sync-ing time with managed time periods the fixed
duration tasks give up the ghost and float about to some unexplained
algorithm.

What makes it worse is the local expectation that fixed work means
fixed start and finish dates. Basically, the PM's want the duration,
start and finish dates to stay fixed and allow units to soar if needed.
Their intention is to then manage the project through working down
over utilized resources.

Any thoughts, direction, or workaround would be appreciated.

 

[Mark Everett | PMP]

In my experience, through testing and observation, Fixed Duration does
best in meeting your PM's needs.

As an example, you have a fixed duration task of 10 days, with 40 hours
work (basicially half time). The resource doesn't do any work on day 1
or 2, so that 8 hours of work that Project was expecting to be done on
those days gets spread over the remaining duration, so the resource
would now have to do 5 hours a day. This will continue until there are
not enough hours in the last day of the task (day 10) to do the work.
That is determined by your Max Hours in a Day setting in PWA/Admin.
Only then will Project push the work out past the previously fixed
duration, and only after telling the PM that will happen.

In Fixed Work or Fixed Units, as soon as the actuals lag, the duration
will extend, at the unit rate, so in my example, missing 8 hours of
work will extend the task by two days, since the resource is working at
50% units.

Hope this helps.
Mark

 

[DSnyder]

Thats what we were hoping as well, but it doesn't seem to work.

The problem is that too often fixed duration tasks don't stay fixed
when PWA time is accepted and when managed time periods sync actual
work protected.

If time is added (actual work, remaining work) when the task hits 100%,
the duration expands.

Specifically what I am looking for are the specific rules, logic and
conditions underlying when the duration on a fixed duration task
changes.

 

[slippymississippi]

Duration changes any time you set the actual finish date to the current
date ahead of the estimated finish date, or any time you record hours
on a task past the expected actual duration.

The only way you can measure that against your original plan is to look
inside your baseline data.

 

[PK Consulting]

Slippy, we're seeing similar things. I knew your second sentence, but I
wasn't sure about the first. Are you saying that completing all of the
scheduled work will cause the actual finish date to change, thus reducing the
duration (fixed duration task)?

Any help would be greatly appreciated because my head is hurting after
beating it against the wall over this issue.

PK Consulting